Windows 7 - Window Photo Viewer Black Levels ?

I was looking at some test patterns on my Windows 7 x64 PC and noticed the black levels were crushed when viewing using Windows Photo Viewer. Any black level with a value of 16 or less gets displayed as 0.

Yet the same images look OK when viewed using HP Photo Viewer, Photoshop Elements, Paint.NET or Irfanview.

The PC came setup with HP Photo Viewer as the default and I changed it to Windows Photo Viewer. I never noticed this problem when using Windows Photo Viewer on my old XP machine, however I might have adjusted the monitor when using Windows Photo Viewer. It’s just been so long I do not recall.

Anyway, Windows Photo Viewer does not match any of the other programs which appear to display proper black levels.

I don’t recall how I set Windows Photo Viewer as the default because there is no .exe file. How can I tell if I am using a 64 bit or 32 bit version, and would this make a difference?

Is there a way to adjust any settings in Windows Photo Viewer?